夜色
Shades of Night
來源：Dario Giannobile｜發表日期：2024-02-28
夜晚的天空是如何變黑的？分階段，從地平線上升起不同的特徵顏色。這幅特寫圖片從左到右顯示了日落後黃昏時間越來越晚的情況，有 20 個不同的垂直色帶。照片是上個月在義大利西西里島錫拉庫薩拍攝的，拍攝方向與太陽相反。最左邊是日落前的上層天空。 右邊突出的波段包括金星帶、藍光波段、地平線波段和紅光波段。隨著地球暗影的升起，這些色帶中的顏色是由太陽光從地球大氣層中的空氣和氣溶膠直接反射、多重反射（有時涉及變紅的日落）以及折射造成的。實際上，這些波段可能是漫反射的，很難辨別，其顏色可能取決於落日附近的顏色。最後，太陽完全落下，天空變得昏暗。不要絕望--當早晨太陽再次升起時，整個過程會反過來發生。
原文：How does the sky turn dark at night? In stages, and with different characteristic colors rising from the horizon. The featured image shows, left to right, increasingly late twilight times after sunset in 20 different vertical bands. The picture was taken last month in Syracuse, Sicily, Italy, in the direction opposite the Sun. On the far left is the pre-sunset upper sky. Toward the right, prominent bands include the Belt of Venus, the Blue Band, the Horizon Band, and the Red Band. As the dark shadow of the Earth rises, the colors in these bands are caused by direct sunlight reflecting from air and aerosols in the Earth's atmosphere, multiple reflections sometimes involving a reddened sunset, and refraction. In practice, these bands can be diffuse and hard to discern, and their colors can depend on colors near the setting Sun. Finally, the Sun completely sets and the sky becomes dark. Don't despair -- the whole thing will happen in reverse when the Sun rises again in the morning.
※ 本文由萌芽機器人自動轉貼自每日一天文圖（Astronomy Picture of the Day，APOD），原文為英文，正體中文是透過 DeepL 翻譯及 OpenCC 進行自動處理，內容僅供參考，若有任何錯誤之處還請見諒！
關於每日一天文圖：每日一天文圖網站是美國國家航空暨太空總署與密西根理工大學提供的服務，網站每天提供一張影像或圖片，並由天文學家撰寫扼要說明其特別之處。